The present invention relates to a piston, especially for an internal combustion engine, with double crank drive.
An internal combustion engine with double crank drive is, for example, known from German patent application 32 38 030 A1. For such a double crank drive each piston is connected with at least one connecting rod to one of the two crank shafts which rotate at the same rpm in opposite directions and are connected to one another by a toothing. An advantage of such a double crank drive is that the piston runs without lateral forces in the cylinder and that the force of the piston is transmitted by at least two connecting rods onto the crankshafts so that the weight of the connecting rods can be reduced and a higher rpm stability can be achieved. Furthermore, with a proper selection of the slanted position of the connecting rod at the top dead center and bottom dead center of the piston the movement kinematics of the piston relative to the rotation of the crankshaft can be designed different from a sine-shaped movement so that the thermodynamic conditions and thus the output development and the torque can be favorably affected.
In general, high requirements are placed on pistons which have a bottom conventionally delimiting the combustion chamber or, in the case of pumps, the working chamber, wherein the bottom has a transition into a mantle at its outer circumference which mantle extends parallel to the cylinder wall. The pistons must be sufficiently resistant to the effects of heat in order to withstand the peak pressures during combustion and the high acceleration and deceleration forces. Furthermore, the pistons should be lightweight so that high masses are not moved unnecessarily in a reciprocating manner.
It is therefore an object of the present invention to provide a piston which has a sufficient stability especially in connection with minimal weight and a simple manufacturing process.